Wireless communication systems may use many techniques to increase throughput and user services. One such technique is carrier aggregation and support of flexible bandwidth. Another technique is to transmit both uplink data and control channels simultaneously. For example, in an advanced long term evolution (LTE-A) compliant system, uplink (UL) channels may be transmitted simultaneously, such as the physical uplink shared channel (PUSCH) and physical uplink control channel (PUCCH).
Carrier aggregation adds complexity to transmit power control schemes in a wireless transmit receive unit (WTRU). A base station, such as an eNodeB (eNB), for example, may have much of the information required for a WTRU to determine its UL power requirements. In single carrier system, the eNB can give the WTRU that information when it gives the WTRU other information. For example, the eNB may provide the WTRU with UL power control configuration data when providing the WTRU with an UL grant. However, when multiple carriers are used and simultaneous transmission of uplink control and data channels is implemented, the WTRU may receive uplink configuration information that is complex. A WTRU may perform complex operations to properly control UL transmission power.